Guiding Options

TEXES has no on-instrument wavefront sensor, and PWFS2 is routinely used for all observations. As the TEXES field of view is small guide stars can be selected down to a radius of 4.3 arc-minutes. The outer limit for PWFS2 guide stars can be displayed on the OT position editor and is discussed here.
If no suitable guide star is available between these limits it may be possible to use a guide star slightly closer in, but if the "shadow" for the PWFS comes close to the slit as drawn then there may be problems. In these cases, discuss the matter with your contact scientist.